Conventional oxygen masks comprise tent like structures which are strapped over the nose and mouth of the patient, often using an elastic band or bands behind the patient's ears or head. Oxygen is fed from a supply through a tube into the bottom portion of the mask at the front of the patient. Many problems exist with such masks, including the fact that many patients find them claustrophobic, the mask must be removed for the patient to speak or eat, thereby discontinuing therapy, and the face mask creates irregular and inefficient infusion of oxygen by the patient since exhaled air from the patient is mixed with oxygen in the mask. Oxygen masks can only be used for oxygen flows greater than 4 liters/minute because exhaled gas accumulates in the mask, and, at lower flow rates interferes with delivery of oxygen-enriched air to the patient.
Conventional nasal cannulae oxygen delivery systems employ an oxygen delivery tube with tubular, open ended nasal prongs at the delivery end of the tube for insertion into a patient's nasal passages. The oxygen delivery tube and nasal cannulae are supported in position by a tube wrapped about the patient's ears or head, making the system both difficult to handle and uncomfortable since it applies downward pressure on the patient's ears when the patient is in a seated position. As well, patients often get nose bleeds from the dryness of the oxygen supplied through the nasal cannulae. Patients also get sores on the ears, face and nose due to the direct contact of the oxygen tubing with the skin. Nasal cannulae can only deliver flows of 0.5 to 4 liters/minute.
Of background interest is Ketchedjian, U.S. Pat. No. 6,247,470 issued Jun. 19, 2001 which describes and illustrates an oxygen delivery apparatus comprising a headset to which is pivotally attached, for rotation in one plane, a flexible arm carrying tubular members for passing oxygen to a patient's mouth. The apparatus is also provided with a carbon dioxide monitoring system.
McCombs et al., U.S. Pat. No. 6,065,473 issued May 23, 2000 describes a somewhat similar apparatus, for non-medical purposes, intended to dispense concentrated oxygen to users, the apparatus comprising an oxygen delivery nozzle attached by an arm extending from a flexible head band, to bathe the user's nose and mouth with oxygen, when in use. Laid-open German Application DE 43 07 754 A1, published Apr. 7, 1994, teaches a system for controlled supply or removal of respiratory air from a user, which system incorporates a mask body held by a rigid air tube over the mouth and/or nose of the user, the air tube being pivotally adjustable in one plane, to enable proper positioning of the mask.
U.S. Pat. No. 3,683,907 of Cotabish issued Aug. 15, 1972 describes and illustrates a fresh air respirator, for use for example by miners, which comprises a cup, supported by pivotable arms in front of the face of the user, a stream of air being conducted to the cup to provide fresh air around the user's nose and mouth.
The applicant has developed a number of lightweight oxygen delivery systems for patients, as described for example in U.S. Pat. No. 6,675,796 issued Jan. 13, 2004, U.S. Pat. No. 6,595,207 issued Jul. 22, 2003 and U.S. Pat. No. 6,450,166 issued Sep. 17, 2002. Also, applicant's U.S. Design Patent Nos. D449,376 issued Aug. 16, 2003 and D449,883 issued Oct. 30, 2001 illustrate designs for such devices. All of these references feature oxygen diffuser devices, designed to create a turbulent oxygen flow, to be situated during use in front of the nose and mouth of a patient, and being held in that area by means of a mount such as a head band, to which is secured a rigid, but bendable oxygen delivery tube. The subject matter of each of these references is incorporated herein by reference.
Other references of general background interest include U.S. Pat. No. 4,282,869 of Zidulka issued Aug. 11, 1981, U.S. Pat. No. 4,018,221 of Rennie issued Apr. 19, 1977, U.S. Pat. No. 5,687,715 of Landis et al. issued Nov. 18, 1997, U.S. Pat. No. 4,465,067 of Koch et al. issued Aug. 4, 1984 and U.S. Pat. No. 5,697,363 of Hart issued Dec. 16, 1977, all of which describe and illustrate different types of head mounted apparatus for delivering oxygen or other gases to a patient.
Most of these prior art devices intended for delivery of oxygen to a patient do not provide the ease of usage, both by health care workers and the patient, and reliability against unintended removal or dislodgement from position, as is required to permit widespread use by the health care profession.
It is desirable to provide an oxygen delivery mask system that provides a suitably high oxygen concentration over a wide range of O2 flow rates. This would permit the use of a single mask for a variety of applications, wherein different flow rates are desirable. It is particularly desirable to provide a mask capable of application as a high flow mask, for use with highly compromised patients. It is desirable to provide a range of flow rates in an open mask that does not trap the exhaled air. It is further desirable to provide a mask that may be readily collapsed into a more compact structure for storage and transport, but which easily snaps back into its use position.
It is an object of the present invention to provide a more versatile, reliable and practical system for delivery of oxygen to patients.